Predictive power of the Berezinskii-Kosterlitz-Thouless theory based on renormalization group throughout the BCS-BEC crossover in two-dimensional superconductors
Year: 2024
Authors: Midei G., Furutani K., Salasnich L., Perali A.
Autors Affiliation: Univ Camerino, Sch Sci & Technol, Phys Div, Via Madonna Carceri 9B, I-62032 Camerino, MC, Italy; Ist Nazl Fis Nucleare, Sez Perugia, Via A Pascoli 23c, I-06123 Perugia, Italy; Nagoya Univ, Dept Appl Phys, Nagoya 4648603, Japan; Nagoya Univ, Inst Adv Res, Nagoya 4648601, Japan; Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Via Marzolo 8, I-35131 Padua, Italy; Univ Padua, QTech Ctr, Via Marzolo 8, I-35131 Padua, Italy; Ist Nazl Fis Nucl, Sez Padova, Via Marzolo 8, I-35131 Padua, Italy; Ist Nazl Ottica, Consiglio Nazl Ric, Via Carrara 2, I-50019 Sesto Fiorentino, Italy; Univ Camerino, Sch Pharm, Phys Unit, Via Madonna Carceri 9B, I-62032 Camerino, MC, Italy.
Abstract: Recent experiments on 2D superconductors allow the characterization of the critical temperature and of the phase diagram across the BCS-BEC crossover as a function of density. We obtain from these experiments the microscopic parameters of the superconducting state at low temperatures by the BCS mean-field approach. For LixZrNCl, the extracted parameters are used to evaluate the superconducting phase stiffness and the Berezinskii-Kosterlitz-Thouless (BKT) critical temperature throughout the BCS-BEC crossover by implementing the corresponding renormalization group (RG) approach. In this way, we make a quantitative test of the predictive power of the BKT theory for evaluating the critical temperature. The RG flow equations turn out to give a sizable renormalization of the phase stiffness and of the critical temperature, which is crucial to obtain a satisfactory agreement between the BKT theory and the experiments, in particular, in the BCS-BEC crossover regime. We predict the temperature range where phase stiffness renormalization can be measured in LixZrNCl across the BCS-BEC crossover. Contrary to other microscopic theories of superconductivity, we find that the BKT theory can be exploited to evaluate quantitatively the critical temperature of 2D superconductors in different pairing regimes.
Journal/Review: PHYSICAL REVIEW B
Volume: 110 (21) Pages from: 214502-1 to: 214502-8
More Information: We acknowledge R. Citro, S. Pilati, and G. Venditti for useful discussions. This work has been supported by PNRR MUR Project No. PE0000023-NQSTI. K.F. and L.S. are partially supported by Iniziativa Specifica Quantum of INFN, by PRIN project Quantum Atomic Mixtures: Droplets, Topological Structures, and Vortices of the Italian Ministry for Universities and Research. K.F. and L.S. acknowledge the project Frontiere Quantistiche (Dipartimenti di Eccellenza) of the Italian Ministry for Universities and Research. L.S. is partially supported by the European Quantum Flagship Project PASQuanS 2, by the NextGeneration-EU within the National Center for HPC, Big Data and Quantum Computing (Project No. 5CN00000013, CN1 Spoke 10: Quantum Computing), and by the BIRD project Ultracold Atoms in Curved Geometries of the University of Padova. K.F. was supported by JSPS KAKENHI (Grants No. JP24K22858 and No. JP24K00557) and the Maki Makoto Foundation.KeyWords: Bose-condensation; Evolution; Density; VortexDOI: 10.1103/PhysRevB.110.214502